---
id: "line-of"
keywords: ["line of"]
name: "__LINE_OF__"
summary: "This is the `__LINE_OF__` special value."
category: "specialvalues"
---

`__LINE_OF__(expression)` returns a tuple consisting of `(line, expression)`, where line is the line number at which the expression you pass as a parameter here appears in the file.

**Note**: `expression` refers to any expression, it does not need to be a function.

<CodeTab labels={["ReScript", "JS Output"]}>

```res example
let f = () => None
let (line, f') = __LINE_OF__(f)

line->Console.log
f'->Console.log

```

```js
function f() {}

console.log(2);

console.log(f);

var line = 2;

var f$p = f;
```

</CodeTab>
